{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,22]],"date-time":"2026-05-22T06:06:22Z","timestamp":1779429982130,"version":"3.53.1"},"reference-count":31,"publisher":"Springer Science and Business Media LLC","issue":"1","license":[{"start":{"date-parts":[[2026,5,22]],"date-time":"2026-05-22T00:00:00Z","timestamp":1779408000000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"},{"start":{"date-parts":[[2026,5,22]],"date-time":"2026-05-22T00:00:00Z","timestamp":1779408000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0"}],"funder":[{"DOI":"10.13039\/501100005722","name":"Ludwig-Maximilians-Universit\u00e4t M\u00fcnchen","doi-asserted-by":"crossref","id":[{"id":"10.13039\/501100005722","id-type":"DOI","asserted-by":"crossref"}]}],"content-domain":{"domain":["link.springer.com"],"crossmark-restriction":false},"short-container-title":["Med Microbiol Immunol"],"published-print":{"date-parts":[[2026,12]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Recent research indicates that the composition of serum anti-SARS-CoV-2 Spike IgG subclass antibodies changes upon repeated exposure to viral Spike. These antibody subclass dynamics were suggested to impact adaptive immune responses and protection against infection. To characterize the role of the IgG subclass composition in the immune response to SARS-CoV-2, assays that measure virus variant-specific anti-Spike IgG subclass concentrations are needed. Here, we describe an easy-to-use serological method for quantifying anti-Spike IgG subclass antibodies against various SARS-CoV-2 variants in multiplex from less than 10 \u00b5L of serum. Our assay enables antigen-independent quantification, making it easily adaptable to emerging variants or other pathogens. We validated our method with 20 sera collected from 10 infection-na\u00efve individuals after the second and third COVID-19 mRNA vaccination. We observed increasing anti-Spike IgG2 and, especially, IgG4 concentrations after the third immunization. More recent Spike variants preserved this pattern with decreased levels of total anti-Spike IgG. Our results showed a strong positive correlation with those from an established flow cytometry-based approach. Our method might help deepen our understanding of immune responses to SARS-CoV-2 and, moreover, help gauge the individual\u2019s protection from severe disease.<\/jats:p>","DOI":"10.1007\/s00430-026-00878-y","type":"journal-article","created":{"date-parts":[[2026,5,22]],"date-time":"2026-05-22T05:18:20Z","timestamp":1779427100000},"update-policy":"https:\/\/doi.org\/10.1007\/springer_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Simultaneous quantification of anti-Spike IgG subclasses against various SARS-CoV-2 variants using a multiplex serological assay"],"prefix":"10.1007","volume":"215","author":[{"given":"Marie L.","family":"Bischof","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pascal","family":"Irrgang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Matthias","family":"Tenbusch","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Oliver T.","family":"Keppler","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Paul R.","family":"Wratil","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"297","published-online":{"date-parts":[[2026,5,22]]},"reference":[{"issue":"27","key":"878_CR1","doi-asserted-by":"publisher","first-page":"2603","DOI":"10.1056\/NEJMoa2034577","volume":"383","author":"FP Polack","year":"2020","unstructured":"Polack FP et al (2020) Safety and Efficacy of the BNT162b2 mRNA Covid-19 Vaccine. N Engl J Med 383(27):2603\u20132615","journal-title":"N Engl J Med"},{"issue":"5","key":"878_CR2","doi-asserted-by":"publisher","first-page":"403","DOI":"10.1056\/NEJMoa2035389","volume":"384","author":"LR Baden","year":"2021","unstructured":"Baden LR et al (2021) Efficacy and Safety of the mRNA-1273 SARS-CoV-2 Vaccine. N Engl J Med 384(5):403\u2013416","journal-title":"N Engl J Med"},{"issue":"7","key":"878_CR3","doi-asserted-by":"publisher","first-page":"1205","DOI":"10.1038\/s41591-021-01377-8","volume":"27","author":"DS Khoury","year":"2021","unstructured":"Khoury DS et al (2021) Neutralizing antibody levels are highly predictive of immune protection from symptomatic SARS-CoV-2 infection. Nat Med 27(7):1205\u20131211","journal-title":"Nat Med"},{"key":"878_CR4","doi-asserted-by":"crossref","unstructured":"Vidarsson G, Dekkers G, Rispens T (2014) IgG Subclasses and Allotypes: From Structure to Effector Functions. Front Immunol, Volume 5\u20132014","DOI":"10.3389\/fimmu.2014.00520"},{"issue":"11","key":"878_CR5","doi-asserted-by":"publisher","first-page":"763","DOI":"10.1038\/s41577-023-00871-z","volume":"23","author":"T Rispens","year":"2023","unstructured":"Rispens T, Huijbers MG (2023) The unique properties of IgG4 and its roles in health and disease. Nat Rev Immunol 23(11):763\u2013778","journal-title":"Nat Rev Immunol"},{"issue":"79","key":"878_CR6","doi-asserted-by":"publisher","first-page":"eade2798","DOI":"10.1126\/sciimmunol.ade2798","volume":"8","author":"P Irrgang","year":"2023","unstructured":"Irrgang P et al (2023) Class switch toward noninflammatory, spike-specific IgG4 antibodies after repeated SARS-CoV-2 mRNA vaccination. Sci Immunol 8(79):eade2798","journal-title":"Sci Immunol"},{"key":"878_CR7","doi-asserted-by":"crossref","unstructured":"Buhre JS et al (2023) mRNA vaccines against SARS-CoV-2 induce comparably low long-term IgG Fc galactosylation and sialylation levels but increasing long-term IgG4 responses compared to an adenovirus-based vaccine. Front Immunol, 13","DOI":"10.3389\/fimmu.2022.1020844"},{"key":"878_CR8","doi-asserted-by":"crossref","unstructured":"Gelderloos AT et al (2024) Repeated COVID-19 mRNA vaccination results in IgG4 class switching and decreased NK cell activation by S1-specific antibodies in older adults, vol 21. Immunity & Ageing, p 63. 1","DOI":"10.1186\/s12979-024-00466-9"},{"key":"878_CR9","doi-asserted-by":"crossref","unstructured":"Kalkeri R et al (2024) Altered IgG4 antibody response to repeated mRNA versus recombinant protein SARS-CoV-2 vaccines. 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Ethics approval was granted by the ethics committee in Erlangen (Az. 340_21B, Az. 46_21B, 350_20B, and 235-18B).","order":3,"name":"Ethics","group":{"name":"EthicsHeading","label":"Ethical approval"}},{"value":"Informed consent was obtained from all individual participants included in the study.","order":4,"name":"Ethics","group":{"name":"EthicsHeading","label":"Consent to participate"}},{"value":"Patients signed informed consent regarding publishing their data.","order":5,"name":"Ethics","group":{"name":"EthicsHeading","label":"Consent for publication"}}],"article-number":"16"}}